pgraph: Move get/set state methods out to resource package

pgraph/pgraph.go

@@ -29,17 +29,6 @@ import (
 	errwrap "github.com/pkg/errors"
 )
 
-//go:generate stringer -type=graphState -output=graphstate_stringer.go
-type graphState int
-
-const (
-	graphStateNil graphState = iota
-	graphStateStarting
-	graphStateStarted
-	graphStatePausing
-	graphStatePaused
-)
-
 // Graph is the graph structure in this library.
 // The graph abstract data type (ADT) is defined as follows:
 // * the directed graph arrows point from left to right ( -> )
@@ -53,9 +42,7 @@ type Graph struct {
 	kv        map[string]interface{}        // some values associated with the graph
 
 	// legacy
-	state     graphState
+	fastPause bool // used to disable pokes for a fast pause
-	fastPause bool        // used to disable pokes for a fast pause
-	mutex     *sync.Mutex // used when modifying graph State variable
 	wg        *sync.WaitGroup
 }
 
@@ -83,9 +70,7 @@ func (g *Graph) Init() error {
 	g.kv = make(map[string]interface{})
 
 	// legacy
-	g.state = graphStateNil
 	// ptr b/c: Mutex/WaitGroup must not be copied after first use
-	g.mutex = &sync.Mutex{}
 	g.wg = &sync.WaitGroup{}
 	return nil
 }
@@ -144,8 +129,6 @@ func (g *Graph) Copy() *Graph {
 		kv:        g.kv,
 
 		// legacy
-		state:     g.state,
-		mutex:     g.mutex,
 		wg:        g.wg,
 		fastPause: g.fastPause,
 	}
@@ -165,24 +148,6 @@ func (g *Graph) SetName(name string) {
 	g.Name = name
 }
 
-// getState returns the state of the graph. This state is used for optimizing
-// certain algorithms by knowing what part of processing the graph is currently
-// undergoing.
-func (g *Graph) getState() graphState {
-	//g.mutex.Lock()
-	//defer g.mutex.Unlock()
-	return g.state
-}
-
-// setState sets the graph state and returns the previous state.
-func (g *Graph) setState(state graphState) graphState {
-	g.mutex.Lock()
-	defer g.mutex.Unlock()
-	prev := g.getState()
-	g.state = state
-	return prev
-}
-
 // AddVertex uses variadic input to add all listed vertices to the graph
 func (g *Graph) AddVertex(xv ...*Vertex) {
 	for _, v := range xv {

resources/pgraph.go

@@ -0,0 +1,75 @@
+// Mgmt
+// Copyright (C) 2013-2017+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package resources
+
+import (
+	"fmt"
+	"log"
+
+	"github.com/purpleidea/mgmt/pgraph"
+)
+
+//go:generate stringer -type=graphState -output=graphstate_stringer.go
+type graphState uint
+
+const (
+	graphStateNil graphState = iota
+	graphStateStarting
+	graphStateStarted
+	graphStatePausing
+	graphStatePaused
+)
+
+// getState returns the state of the graph. This state is used for optimizing
+// certain algorithms by knowing what part of processing the graph is currently
+// undergoing.
+func getState(g *pgraph.Graph) graphState {
+	//mutex := StateLockFromGraph(g)
+	//mutex.Lock()
+	//defer mutex.Unlock()
+	if u, ok := g.Value("state"); ok {
+		return util.Uint(u)
+	}
+	return graphStateNil
+}
+
+// setState sets the graph state and returns the previous state.
+func setState(g *pgraph.Graph, state graphState) graphState {
+	mutex := StateLockFromGraph(g)
+	mutex.Lock()
+	defer mutex.Unlock()
+	prev := getState(g)
+	g.SetValue("state", state)
+	return prev
+}
+
+// StateLockFromGraph returns a pointer to the state lock stored with the graph,
+// otherwise it panics. If one does not exist, it will create it.
+func StateLockFromGraph(g *pgraph.Graph) *sync.Mutex {
+	x, exists := g.Value("mutex")
+	if !exists {
+		g.SetValue("mutex", &sync.Mutex{})
+		x, _ = g.Value("mutex")
+	}
+
+	m, ok := x.(*sync.Mutex)
+	if !ok {
+		panic("not a *sync.Mutex")
+	}
+	return m
+}

util/interfaces.go

@@ -25,3 +25,12 @@ func Bool(x interface{}) bool {
 	}
 	return b
 }
+
+// Uint returns the interface value if it is a uint, and otherwise it panics.
+func Uint(x interface{}) uint {
+	u, ok := x.(uint)
+	if !ok {
+		panic("not a uint")
+	}
+	return u
+}